Paraproteinemic Renal Diseases that Involve the Tubulo-Interstitium

Department of Pathology, St. Louis University, St. Louis, Mo., USA.
Contributions to nephrology (Impact Factor: 1.8). 02/2007; 153:105-15. DOI: 10.1159/000096763
Source: PubMed


The renal response to deposition of monoclonal light chains represents a spectrum of pathologic changes that can be divided into glomerular or tubulo-interstitial processes. Involvement of the tubulo-interstitium can include activation of the proximal tubule, proximal tubule injury/cell death, and cast nephropathy. In these diseases, the culprit is not the intact immunoglobulin protein but instead the immunoglobulin light chain. Recent noninvasive tests, including immunofixation electrophoresis or quantification of serum free light chains, have increased the sensitivity for detection of an abnormality in circulating free light chains and are invaluable ancillary tools, but short of renal biopsy, the diagnosis of these diseases can prove challenging. A description of the pathobiology and overview of the approach to management of these light chain-mediated renal lesions is provided.

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    • "As a consequence, large amounts of FLCs reach the distal tubule lumen where they interact specifically with Tamm-Horsfall proteins (THPs; also known as uromodulin), generating myeloma casts. Cast formation in the distal tubule can block glomerular flow and cause proximal tubular atrophy [19], also contributing to interstitial fibrosis [20]. Simultaneously, the massive reabsorption of monoclonal FLCs within the proximal tubules induces proximal tubule cells apoptosis and DNA degradation, resulting in critical morphologic changes, such as epithelial-to-mesenchymal transition (EMT) or necrosis [21]. "
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